At what speed are we moving?

Thats is to say all of us here, in our solar system, what speed are we moving with?

What if we are moving with a speed near to light, how would we know it. The universe is expandning, so we must be moving catch my drift, what speed are we moving at?








Hehehe

I think we (as the planet) are moving at around a kilometre a second. Pretty fast really. Not sure how fast everything is moving though.

Well... I do know we are moving pretty crazy fast, and that every few billion years we make a revolution around the galaxy, but nothing approaching the speed of light.

As for measuring our speed outside the galaxy, unfortunately then you start dealing with universal expansion which, because space-time itself is expanding, means that even though we might be receding from other galaxies at nearly, or past light speed - doesn't mean that we actually are, and are not breaking any physics in the process.

Originally posted by Yarium
Well... even though we might be receding from other galaxies at nearly, or past light speed - doesn't mean that we actually are

How is that? Wouldnt it make our speed near to light speed?

What im getting at is that perhaps your mass doesnt change even if you move at speed of light, and perhaps time is not changed also?

How fast we are moving

That should help you out.

I wonder what happens to speed of an object when it stops in relation to everything around it. What is the speed of stop? Can we ever be at zero velocity withen a galaxy? Lots of questions.

I know it's a difficult concept to understand, but just because the galaxies are flying away from each other (at least, most outside of our "Local Group") - does not mean that they are actually moving away.

In fact, from the view of someone in that galactic cluster, it would look like ALL other galaxies are moving away from them. The same goes for all other galactic clusters.

Like I said, this is because space-time is expanding. The distances between galaxies are growing not because they are moving, but because the area between them is growing.

Imagine this. You have a water mattress, where the rubber on it can expand infinitely. Now, place some bowling balls on the mattress, and start pumping water into them. The bowling balls won't start moving, but they'll make dents in the mattress. In fact, the distance (from your point of view) is that the bowling balls aren't moving, and are staying exactly where they started.

However, if you were to measure the distance to each bowling ball by putting a tape-measure across the surface of the ever-expanding bed, you would find that the 2-dimensional distance between the bowling balls is increasing!

Now, let's make this more "universal" and more to the point with the speed of light. Let's say you made this mattress absolutely MASSIVE! And you also place a bunch more bowling balls on it. If you could fill it up with water at the same speed as before (so the expansion of the mattress takes place at the same pace), then you would find more interesting things.

The further away a bowling ball was from another bowling ball, the faster the 2-dimensional distance between them would increase (as there's more room for more water, which means more expansion). If the mattress was large enough, it would actually seem like the 2-d distance between them would, eventually, be growing at past the speed of light! This is because the expansion of each individual piece of space on the mattress is happening the same everywhere, it's not flowing out from a specific place.


Now, take everything I just told you, and move it up 1 dimension. 3-dimensionally the galaxies appear to be moving away from each other at an ever increasing pace (and at really far away galaxies, at more than the speed of light). Perhaps 4-dimensionally they are not, and if we could "pick them up" off the mattress, and then move them, they would appear to move faster than light, even though they're just skipping all the curves in space that exist.

Do you understand now?

The planet at about 30KM/s around the sun.

About 300m/s around its own axis.

Milkyway is moving towards Andromeda Galaxy at about 33KM/s and they are 2.3 Million lightyears apart.

Dunno exacrly what speed sol goes about in the galaxy, but with the following data you can callculated:

Sol Distance from Center of Milky Way 28,000 light years.
Sol time to do 1 rotation around Milky Way 225 Million years.

Heres a (probably idiotic) thought, if the earth is travelling at 30km/s around the sun, then why, the second a spacecraft leaves the earth, the occupants of the spacecraft dont see earth shoot off far far away in around 5 minutes?

Originally posted by Shadow88
Heres a (probably idiotic) thought, if the earth is travelling at 30km/s around the sun, then why, the second a spacecraft leaves the earth, the occupants of the spacecraft dont see earth shoot off far far away in around 5 minutes?

The spacecraft and earths momentum is the same. If we could somehow build a crft that would "lock" itself in space relative to the sun and the stars, then we'd see the Earth move away from us at 30km/sec.

It would take an extremely large amount of energy to do this though.

Velocity being relative, wat are we moving in relation to? The earths axis? The sun? Nibiru? If you believe you're one with the universe then you're not moving anywhere, as "you" would "be" the entire universe. Can we be moving in relation to spacetime or superstrings? How does Hawking Radiation fit in?

Summat to think about.

Take a philosophy class of space and time like I did and you will learn that there is no such thing as stop, because in order to assume a stopped position, you are forced into accepting that space is an actual measurable quanitity and that inplies that space is a thing. If you keep going down this line of deductions, it contradicts everything about einstein theories and the such. Speed is only measurable based on a refernce point, like a star or a planet, but it is impossible to measure your speed in absolute space because space is not a thing, it has no markers, ir has to refernces, it is just space. So if you had no refernce point, you have no speed.

Train

Originally posted by Shadow88
Heres a (probably idiotic) thought, if the earth is travelling at 30km/s around the sun, then why, the second a spacecraft leaves the earth, the occupants of the spacecraft dont see earth shoot off far far away in around 5 minutes?

Because you are also traveling at 30km/s around the sun. When you leave the earth, you are traveling around the earth, with respect to the earth. You have only slighty increased, or decresed, depending on refernce, your velocity relative to earth. You have not jumped off the earth and landed on a frition surface of space and slowed down to see the earth take off. Like this, drive a car at 50 mph, and hold a baseball out the window and barely push it out. Imagine now that there is no air friction or gravity. That ball will continue on its path at the same velocity of the car + the speed and direction which u pushed it. The velocity of the car dominates so the baseball barely moves away, but still, it doesnt just stop and see the car take off. expand to fit the description of the ship but much more complicated with gravitational pulls of earth.

Train

How fast around the sun is slow. How fast the galaxy is moving with our solar system with earth is millions of miles a second.
We are traveling at millions or billions if not more M/PS.
One second ago you were lightyears away.

[edit on 15-12-2005 by Wisdumb]

Actually, according to the website given, the actual speed that the galaxy is travelling at within the Local Group of galaxies is 300km/sec. So, no, we are not millions of miles away than a moment ago - but 300 km is a good amount.

Actually, so long as we confine ourselves to the local group, the fastest earth could possibly be moving at is 580.5km/sec (add up every number there - for at the fastest moment, we are going around the galaxy in the same direction the galaxy is moving, and also going around the sun in the same way the galaxy is moving, and also going around the earth at the same speed the galaxy is moving.

The slowest speed would be 19.5km/sec - which is still amazingly fast - but a far cry of the 580.5km/s

To answer the question of how fast we're (the Earth & us) moving, you first have to determine, "Compared to what"? Otherwise the question has no meaning.

Due to results obtained from the COBE satellite, which launched back in 1989 to take some measurements of the cosmic microwave background radiation (CBR), a very good universal frame of reference was discovered. Since the CBR permeates ALL of space, the CBR itself can be used as such. Not only that, but using the CBR as a frame of reference also allows us to define a direction.

So, compared to the cosmic microwave background radiation, we are moving through space at the breakneck speed of 390km/s. That's equivalent to 1,404,000km/hour, or 872,405.15 miles per hour. The direction we're going in at this speed is also well defined. If you go outside and locate the constellation Leo (the Lion) in the night sky, then you are looking in the direction we're headed.

Good question ...

That makes me think, is it possible for something to just be sitting in space and not moving ? if it was would we know it being that we are moving so fast ? It wouldnt be like driving past someone in a car, from our planet we really dont have a reference. I mean things could just be sitting there, and it would look as though its moving toward or away from us. I know its off topic but just a brain spill i had to get out.

Unfortunately, no, it's not possible for something to not be moving in space - as there is no standing point of referance in space. It's like trying to identify the "centre" on the surface of a basketball without telling someone it's inside the basketball. The centre of the universe is the beginning of time.

So, because of that, no point is the centre, and every point is the centre. This makes trying to say that an object is moving, or isn't moving, is only able to be measured by referance to another object.

Neeto, eh?

Are accelerometers very accurate? Couldn't you use one of those to completely stop by detecting your motion or lack thereof? The only reference point we need is the closest planetary body, if it starts to move away in it's orbit then you've effectively come to a full stop.

I found a good answer to the question here: LINK

Its interesting to wonder how fast the earth is moving relative to what.

Exactly, those are referance points. It's like drawing one dot on the ball in red, and another in blue, and measuring the length between them. It works, but only to a point. Remove the other dot... and you're left with nothing. Add to that our universe is such a big basketball that even if we can see our own galaxy as the line comes back round to us, that we can't even tell that a dot's there - much less identify it as ours. Add again to this that because the speed of light is finite, what we're looking at isn't even us yet, and so we have no hope of seeing our beginnings.